The invention relates to a magnetic coupling arrangement for transmitting torque from an input shaft to an output shaft, whereby at least one magnet arrangement is assigned to the input shaft and to the output shaft, and whereby a containment shell comprising at least one inner sleeve and at least one outer sleeve extends between the magnet arrangements.
Such magnetic coupling arrangements are used for the contact-free transmission of forces, e.g., between two hermetically sealed separate spaces, which are coupled by magnetic fields alone without any additional mechanical connections. The magnetic couplings may be used with magnetic pumps or the like, for example. In addition, such coupling systems may be used for agitators, blowers, mixers, centrifuges or similarly moving apparatuses.
The containment shell of such magnetic couplings can be manufactured, for example, of non-metallic materials such as ceramics, carbon fiber composites or synthetics.
Such containment shells do not have any eddy current losses, however, the use of these containment shells is significantly limited due to the rising pressures and temperatures. In addition, all-metal containment shells are known. Due to moving magnetic fields, high eddy currents arise in metallic containment shells, requiring additional drive loads, which is reflected in the form of heat in the magnetic space.
The eddy currents increase as the transfer performance, the containment shell wall thickness and/or the circumferential speed of the magnetic coupling increases, such that the efficiency of, for example, magnetic couplings with a metallic containment shell is influenced negatively. Furthermore, magnetic coupling arrangements are known that exhibit a containment shell with a so-called sandwich design.
Such a containment shell is known from the German Patent No. 689 15 713. This patent discloses a low-loss, synchronous, magnetic drive system that comprises a magnetic coupling arrangement, whereby the magnetic coupling exhibits a containment shell comprising an inner sleeve and an outer sleeve. With the known drive system, the inner sleeve is designed with numerous parallel core laminations or ring elements, respectively.
This has the disadvantage of requiring numerous components for the inner sleeve. In addition to increased manufacturing and assembly costs, another disadvantage is that the individual core laminates must be aligned to each other during assembly.
A relatively large portion of the volume of the part of the cylinder that is pressurized and to some degree exposed to aggressive media is not made of metal but of flat gasket material.
Furthermore, various elastomers are necessary for sealing the pressure cylinder with said elastomers being located in the product space just as the spring component. The outer body does not form an additional sealed protective sleeve. In addition, maintenance costs for a containment shell designed in this manner are relatively high because disassembly and reassembly of the containment shell is time-consuming due to the many components.